OS X Mountain Lion's new Do Not Disturb feature for Notification Center is great for shutting down notifications for a set amount of time, but unfortunately you can't set it to a schedule. Apple blog TUAW shows how to use Automator to tie Do Not Disturb to your calendar.

The process involves setting up a simple Applescript with Automator, and then tying that to a Calendar alarm. From there, you simple set up your Calendar with the time you want Do Not Disturb to start running, and you're all set. Since it's linked to your calendar, that means you can set Do Not Disturb to automatically turn on every time you're in class, have a meeting, or when you just need to get work done. Head over to TUAW for all the code you need and a full guide.